The present invention relates to an intake manifold which mixes recirculated exhaust gas (EGR) with the fresh air for a diesel engine.
There is a need for a diesel engine which meets Tier 3 emission regulations. To effectively meet the emissions requirements with minimal impact of fuel economy and engine durability, the EGR and fresh air must be evenly mixed and evenly distributed among the cylinders. Previously, EGR and fresh intake air has been mixed with apparatus which includes venturi type inlets, or mixing devices which require additional parts and controls.
To reduce costs, it would also be desirable to have an engine EGR system which permits EGR flow rate to be determined by measuring a temperature differential and without sensing a pressure differential across a flow element such as a venture and without using a flow meter. This requires even EGR/fresh air mixing. But, it very difficult to mix EGR and air evenly and quickly because EGR and fresh air have significantly different densities.
It would also be desirable to have an EGR/fresh air mixing intake manifold which can be placed in different orientations so that the fresh air intake can be oriented upwardly or downwardly.